Intravenous (‘IV’) therapy is primarily used for the delivery of fluids into the vascular system of a patient. Medical implements associated with IV therapy, such as catheters and cannulas, can be inserted into a patient's blood vessel by using an insertion device. Insertion devices may comprise a needle on which a medical implement may be mounted and which guides the medical implement into a blood vessel, typically a vein, before the needle is withdrawn leaving the medical implement in the vein.
Standard insertion devices, after use, represent a health hazard in that they are a primary source of needlestick injuries and scratches. Such injuries heighten the risk of contamination and the transmission of diseases such as AIDS and hepatitis, which are present in or on the insertion device or in residual bodily fluids withdrawn with the device from a patient's vein. It is this residual fluid that is directly responsible for the transmission of diseases via needlestick injuries or scratches.
A number of safety insertion devices have been produced whereby the needle is safely retracted into the device. These types of safety devices can be generally divided into two types: ‘active’ insertion devices and ‘passive’ insertion devices. ‘Active’ insertion devices have a safety mechanism which is activated by the user after use of the insertion device whereas ‘passive’ insertion devices have safety mechanisms that do not require any action from the user.
Despite the benefits offered by the safety insertion devices over standard insertion devices a number of problems still exist. ‘Active’ insertion devices require users to be trained in the effective use of the device. Incorrect use of the device may result in the premature activation of the safety mechanism resulting in a device that then cannot be used, or worse, no activation after use which presents a needlestick injury risk.
‘Passive’ insertion devices can be unreliable in the automatic activation of the safety mechanism. For instance, the safety mechanism may activate prematurely or not at all. Due to the nature of their construction they contain many parts, which due to the large scale of manufacturing, are prone to failure.
Additionally, in general due to the extra parts involved in the manufacturing of safety insertion devices over standard insertion devices, both ‘active’ and ‘passive’ insertion devices tend to cost more.
When the safety mechanism of a safety insertion device is a retractable needle, the retraction mechanism tends to be spring loaded. The spring provides for an effective retraction force. A by product of the retraction force is that the retraction process can produce a retracting shock. Such shocks can cause residual fluid in the device to spray or squirt out of the rear of the device in what is known as ‘splatter’. Such an effect is highly undesirable as it can cause cross contamination by direct contact with the residual body fluid or by breathing in splatter which is atomized in the air.
Finally, both ‘active’ and ‘passive’ safety insertion devices which are manufactured in a pre-assembled state with a medical implement are prone to becoming temporarily stuck to the medical implement. Such a situation, referred to as ‘stiction’, is undesirable especially once the safety insertion device has been used to insert the medical implement into a vein. The actions involved in disengaging the safety insertion device from the medical implement can lead to the premature activation of the safety mechanism in an ‘active’ safety insertion device or can damage the safety mechanism in both ‘active’ and ‘passive’ safety insertion devices to the extent that the safety mechanism is no longer functional. More importantly, such actions heighten the risk of a user obtaining a needlestick injury and the risk of a user being exposed to bodily fluids.
Thus, there is a need for a safety insertion device which is simple and reliable to use.